Cleaning apparatus for a sheet delivery mechanism

ABSTRACT

In printing apparatus, an endless chain conveyor on its return from delivery of a freshly printed and powdered sheet is cleaned by passage through a generally closed housing having brush and air nozzle means impinging on the chain and grippers thereof and exhaust means to induce an inward air flow at the entrance and exits parts of the housing.

Preuss ,et al.

CLEANING APPARATUS FOR A SHEET June 25, 1974 [54] 407,309 7/1889 Warsop 15/308 x DELIVERY MECHANISM 1,089,453 3/1914 Wood 15/308 UX 1,239,815 9/1917 Peters et a1. 118/70 X Inventors: ried c uss,- prend11ngen; 1,696,171 12/1928 Lipsius 118/312 x Claus Simeth, Offenbach, both of 1,698,405 1/1929 Johnson 118/70 X Germany 2,003,267 5/1935 Smith et a1... 118/312 X 2,015,583 9 1935 B t h I5 308 Assigneel Roland Pffsetmachinenfabrik Faber 2,181,266 1111939 D2111; 15/308 x & Schlewher AG, Postfach, 2,759,449 8/1956 Lindquist 118/312 x Germany 2,889,805 6/1959 Freeder 1 18/70 UX [22] Fil d; S t, 28, 1972 FOREIGN PATENTS OR APPLICATIONS I 6,929 3/1902 Austria 15/308 1211 Appl' 293065 488,360 12/1929 Germany 15/308 629,418 4/1936 Germany 15/308 [30] Foreign Application Priority Data M Primary Examiner orris Kaplan S 30,1971 G 2148757 em ermany Attorney, Agent, or FirmWo1fe, Hubbard, Leyd1g, 52 us. (:1 198/180, 118/70, 198/229, V0118 08am, Ltd

101/416 R;423 51 1111. c1. B65g 45/00 1571 ABSTRACT [58] Field of Search 118/70, 50,501; n p int ng apparatus, an endless chain conveyor on its 15/306 A, 308; 198/229, 230; 1 17/1 NQ; return from delivery of a freshly printed and powdered 271 NQ sheet is cleaned by passage through a generally closed housing having brush and air nozzle means impinging [56] References Cited on the chain and grippers thereof and exhaust means UNITED STATES PATENTS to induce an inward air flow at the entrance and exits 41,029 12/1863 Tapley 118/308 x parts of the housmgf 311,612 2/1885 Schneider 118/308 X 5 Claims, 4 Drawing Figures- 45 CHAIN CONVEYOR? VIII/I PATENTED JUN 2 5 I974 SHEET 1 BF 2 CHAIN CLEANING APPARATUS FOR A SHEET DELIVERY MECHANISM In sheet fed presses it is common to use powder applicators to spray powder onto freshly printed sheets in order to eliminate offsetting and smudging problems as the sheet is transferred from the printing press tothe delivery pile.

An undesirable drawback of such procedure, however, is that the sheet transferring conveyor chains will be contaminated. This eventually results in jamming of the sheet grippers affecting proper discharge of the sheets upon the delivery pile.

It is a primary object of the present invention therefore to provide a device which will prevent the accumulation of powder on the endless chain conveyor in order to improve the operating reliability and life of the sheet delivery mechanism, enabling maintenance intervals to be increased. It is a further object to provide a cleaning apparatus so constructed and arranged that it does not interfere with the sheet transfer.

Further objects of the invention will be apparent from the following detailed description of the preferred embodiments thereof made with reference to the accompaning drawings forming a part of this specification, and in which:

FIG. 1 is a diagrammatic side elevational view of a delivery mechanism for a sheet-fed printing press embodying the present invention.

FIG. 2 is a sectional view of the cleaning apparatus taken on section line 2-2 of FIG. 3.

FIG. 2a is a diagram showing use of cooperating rotary brushes.

FIG. 3 is a sectional view looking along section line 33 in FIG. 2. v

Referring now more particularly to the drawings there is shown in FIG. 1 a chain conveyor 2 having lower and upper portions defining delivery and return runs respectively. The sheets 1 are transferred from a conventional lithographic printing press (not shown) and moved along the lower run of the chain to a position over the delivery pile 3 where they are released and allowed to drop onto the pile. The conveyor 2, as is well known, is formed of endless chains 4,5 mounting a series of gripper assemblies 6 (see also FIG. 3)..The sheets are released onto the delivery pile 3 by conventional means with the help of a braking device 7 at the rear edge and a jogger device 8 at the leading edge of the pile. The sheets in the pile are supported by a pile board 9 arranged to be progressively lowered by a conventional pile elevator 10 as the height of the pile increases.

It will be understood that sheets 1 as they arrive fresh from the press are, during transfer, coated with absorbent powder, as is well known in the art, and it will also be understood that some of the powder will be deposited, rather unavoidably, on the chain and grippers.

According to the invention there is provided a cleaning apparatus incorporating an evacutated housing mounted at right angles to the running direction of the chain conveyor and extending transversely over the width of the conveyor having diametrically disposed openings in the side walls thereof which define the passage through which the chain conveyor passes, the casing including at least one pair of brushesextending transversely of the width of the conveyor and being disposed opposite each other to allow the chain conveyor to pass between the brushes. Preferably two pairs of brushes are used, spaced along the path of conveyor movement.

In the illustrated embodiment, the cleaning apparatus identified as 11 is mounted to cooperate with the return run 2a of the endless chain conveyor i.e., in the region following release at the delivery pile 3 (FIG. 1). The cleaning apparatus is formed of cooperating upper and lower sections 12,13 (FIG. 2) defining an inletopening 45 and an outlet opening 46 extending transversely of the entire width of the conveyor 2, the ends of the sections 12,13 being enclosed by side plates 14,15. On the side plates 14,15 there are mounted supporting angles 16,17 respectively which may be screwed onto the supporting angles 20,21 fixed to the side frames 18,19 of the delivery mechanism. The upper section 12 is fixed to the side plates 14,15 by means of screws 24,25 and may be loosened from the lower section 13 of the housing. Inside of the upper section 12 of the housing there are provided mounting angles 26,27 (FIG. 2) on which brushes 28,29 are fastened. Inside the lower section 13 there are provided further mounting angles 30,31 on which brushes 32,33 are fastened, the latter cooperating with the respective brushes 28,29. The lower section 13 of the housing is preferably formed as a funnelshaped trough or receptacle, the bottom of which has an opening 34 through which the dust brushed off from the gripper assemblies 6 may be exhausted. Communicating with the opening 34 is a suction tube 35 which leads, via a chamber 36, to an exhaust fan (not shown). It will be understood that each gripper assembly 6 (FIG. 2 or 3) comprises a rotably supported gripper shaft 37 with gripper elements 38 mounted thereon as well as a gripper pad bar 39 having gripper pads 40 mounted thereon. The gripper assemblies are supported by means of studs 41,42 between the endless chains 4,5 running on chain guides 43,44. Since the brushes bridge the chains all portions of the conveyor are subject to the action of the bristles.

The operation of the cleaning apparatus is as follows: Referring to FIG. 2, the gripper assemblies 6 enter the cleaning apparatus 11 through the opening 45, on the upstream side and pass between the successive pairs of brushes 28,32 and 29,33, with the result that any powder is removed by the action of the brushes. After having passed the last set of brushes the gripper assemblies leave the cleaning apparatus through the downstream opening 46. The powder removed from the gripper carriages falls down into the funnel-shaped lower section 13 of the casing 11 where it is exhausted through the suction tube 35.

In accordance with one of the aspects of the invention the brushes may be of the rotary type extending the width of the conveyor as is shown at 28a,32a in FIG. 2a in lieu of fixed brushes 28,32. The rotary brushes may be of cylindrical shape mounted on respective shafts journaled in suitable bearings (not shown). Furthermore, if desired, the housing may be equipped with blast nozzles N which may be connected to a suitable source of compressed air and directed against the chain conveyor in order to augment the cleaning operation of the brushes. Due to the construction and evacuation of the housing the disposed powder The inlet opening 45 and outlet 46 provide the sole communication with ambient air so that there is an induced inward flow of air through the opening to prevent unwanted escape of the powder outwardly of the openings. Preferably the vacuum in the suction tube 35 is made sufficiently great so that the rate of air flow through the suction tube substantially exceeds the rate of air flow through the nozzles and so that, notwithstanding the nozzles, there is a net inward flow of air through the openings 45,46.

What we claim is:

1. In a delivery mechanism for sheet fed printing presses in which grippers for the sheets are provided on an endless chain for conveying the sheets fresh from the press to a delivery pile and for travel along a return path back to the press after the sheets have been deposited on said delivery pile and in which means are provided in the path of movement of the conveyor from the press to the pile for dusting the sheets with powder, the improvement which comprises a cleaning apparatus in the return path having means impingeing upon the chain and grippers continuously incident to the movement thereof for mechanically dislodging and evacuating the powder deposited thereon, said cleaning apparatus and means thereof comprising:

a housing having entrance and exit means through which said chain and grippers travel;

pairs of opposed brushes disposed within said housing and each opposed brush in contact with substantially all portions of said chain and grippers which travels therebetween;

air nozzle means disposed within said housing and directed at said chain and grippers;

vacuum means to exhaust said housing whereby to remove all powder dislodged by said brushes and air nozzles and whereby to induce air flow inwardly through said entrance and exit means to inhibit escape of dislodged powder.

2. The combination as claimed in claim 1 in which the brushes are mechanically driven.

3. The combination as claimed in claim 1 in which the rate of air flow through the vacuum connection exceeds the rate of air flow through the nozzle means.

4. The combination as claimed in claim 1 in which the housing includes an upper portion and a lower portion defining said entrance and exit means and wherein said upper and lower portions are separable to permit installation around an existing endless chain while keeping the chain intact.

5. The combination of claim 1 in which the vacuum means is provided at the bottom of said housing. 

1. In a delivery mechanism for sheet fed printing presses in which grippers for the sheets are provided on an endless chain for conveying the sheets fresh from the press to a delivery pile and for travel along a return path back to the press after the sheets have been deposited on said delivery pile and in which means are provided in the path of movement of the conveyor from the press to the pile for dusting the sheets with powder, the improvement which comprises a cleaning apparatus in the return path having means impingeing upon the chain and grippers continuously incident to the movement thereof for mechanically dislodging and evacuating the powder deposited thereon, said cleaning apparatus and means thereof comprising: a housing having entrance and exit means through which said chain and grippers travel; pairs of opposed brushes disposed within said housing and each opposed brush in contact with substantially all portions of said chain and grippers which travels therebetween; air nozzle means disposed within said housing and directed at said chain and grippers; vacuum means to exhaust said housing whereby to remove all powder dislodged by said brushes and air nozzles and whereby to induce air flow inwardly through said entrance and exit means to inhibit escape of dislodged powder.
 2. The combination as claimed in claim 1 in which the brushes are mechanically driven.
 3. The combination as claimed in claim 1 in which the rate of air flow through the vacuum connection exceeds the rate of air flow through the nozzle means.
 4. The combination as claimed in claim 1 in which the housing includes an upper portion and a lower portion defining said entrance and exit means and wherein said upper and lower portions are separable to permit installation around an existing endless chain while keeping the chain intact.
 5. The combination of claim 1 in which the vacuum means is provided at the bottom of said housing. 